Croatia has been given the conditional go-ahead to join the EU, after six years of preparations marred by slow democratic reforms in Zagreb and the EU’s reluctance to expand.

The former Yugoslav state of 4.4 million people should be able to wrap up accession negotiations next week, EU leaders said at a summit in Brussels, but warned the Zagreb government that it has to continue to fight widespread corruption with “vigour”.

The recommendation marks a turnaround for Croatia, which struggled for years to convince the EU’s 27 governments that its judiciary reforms will produce genuine results and prove it has recognised its role in the Balkan wars in the 1990s.

However, its efforts will face more EU scrutiny in the coming months, and its hopes of joining the EU in July 2013 could be jeopardised if reform slip-ups persuade some of the EU’s national parliaments to delay ratifying the accession treaty.

Many EU politicians are hopeful that rewarding Croatia for a last-minute reform push would persuade other governments in the western Balkans that the EU is willing to accept new members if they are ready.